test/wcc/data: grow the declarative compiler corpus to 1,224 fixtures

The r-prefixed waves absorb the runtime, reject, and byte-compare rows
of the migrated native carriers; each fixture is one directory with one
case.ww and a //ww:error, //ww:compile, //ww:run, or //ww:run-exit
directive covering both frontends.

test/wcc/data/r778_stream_setflush/case.ww

@@ -0,0 +1,26 @@
+//ww:run-exit 54
+// Migrated from 778_bufio_vstream_run row stream_setflush.
+package main;
+import os;
+import bufio;
+import memio;
+import io;
+export fn main() i32 = {
+    let sinkbuf: [16]u8;
+    let sink: memio.stream = memio.fixed(sinkbuf[0:16]);
+    let sinkvs: io.stream = &sink.vt;
+    let rb: [4]u8;
+    let wb: [8]u8;
+    let b: bufio.stream = bufio.init(sinkvs, rb[0:4], wb[0:8]);
+    let bvs: io.stream = &b.vt;
+    let semi: [1]u8;
+    semi[0] = 59u8;
+    bufio.setflush(&b, semi[0:1]);
+    let payload: [3]u8;
+    payload[0]=97u8; payload[1]=98u8; payload[2]=59u8;
+    let wr = io.write(bvs, payload[0:3]);
+    if (!(wr is size)) { return 81; };
+    if (sink.pos != 3) { return 82; };
+    if (sinkbuf[0] != 97u8 || sinkbuf[2] != 59u8) { return 83; };
+    return 54;
+};